Altered Cardiac Repolarization in Chronic Obstructive Pulmonary Disease.

OBJECTIVE

Altered cardiac repolarization is an important mechanism in the development of malignant cardiac arrhythmia and in the occurrence of sudden cardiac death. It is known that the risk of cardiac arrhythmia and sudden death is increased in patients with chronic obstructive pulmonary disease. Evaluating the measurements of repolarization in the electrocardiogram may provide useful information to determine potential risks for lethal arrhythmias in the patients with chronic obstructive pulmonary disease. In the present study, we investigated the possible relationships between repolarization parameters in the electrocardio and demographic, clinical, and biochemical findings in patients with chronic obstructive pulmonary disease.

MATERIAL AND METHODS

In the present study, 35 patients with Global Initiative for Chronic Obstructive Lung Disease A-B constituted group 1 and 35 patients with Global Initiative for Chronic Obstructive Lung Disease C-D constituted group 2. Cardiac repolarization and dispersion (QTc interval and QT dispersion) were measured on 12-lead electrocardiogram. QTc interval, QT dispersion, TP-e, and Tp-e/ QTc were evaluated in order to determine the patients at risk of sudden cardiac death. QTc interval >440 ms in men and >460 ms in women was considered as prolonged QTc interval.

RESULTS

QTc and QTd values were found to be statistically significantly prolonged in the group of GOLD C-D compared to the group of GOLD A-B (P < .001). QTc value showed negative correlation with the ratio of forced expiratory volume in 1 second to forced vital capacity and partial pressure of oxygen (P = .030, r = -0.260; P = .006, r = -0.332, respectively). No significant difference was in Tp-e and Tp-e/QTc between the groups (P = .73, P = .12, respectively).

CONCLUSION

QTc and QTd are non-invasive markers reflecting arrhythmogenicity, and our findings were found to be related to prolonged QTc and QTd in patients with chronic obstructive pulmonary disease. Prolongation in the dispersion of repolarization and altered cardiac repolarization in the population with chronic obstructive pulmonary disease may be related to hypoxemia and airway obstruction. Alterations in the cardiac repolarization may put these patients at high risk for malignant ventricular arrhythmia and sudden cardiac death.